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Intro to Ratios. A RATIO is a comparison of 2 numbers. Kathlene can write her ratio of baskets made to attempts in three different ways. 17 25. 17 to 25. 17:25. Example:
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A RATIO is a comparison of 2 numbers. Kathlene can write her ratio of baskets made to attempts in three different ways. 17 25 17 to 25 17:25 Example: In basketball practice. Kathlene made 17 baskets in 25 attempts. She compared the number of baskets she made to the total number of attempts she made by using the ratio 17 25 .
Additional Example 1: Writing Ratios The recommended fuel for Suzanne’s snowblower is made from 80 quarts of gasoline and 1 quart of motor oil. Write each ratio in all three forms. A. quarts of gasoline to quarts of motor oil For every 80 quarts of gasoline there is 1 quart of oil. 80 1 , 80 to 1, 80:1 B. quarts of oil to quarts of fuel mixture Find the total number of quarts in the mixture. 80 + 1 = 81 1 81 , 1 to 81, 1:81 For each quart of oil there are 81 quarts of mixture.
Ratios . Just like any fraction, ratios can be reduced to lowest terms equivalent ratios Ratios that name the same comparisons To see if to ratios are equivalent • Change each to a decimal and compare the decimals. • Or 2. Reduce both ratios and compare.
Example 1-1a Write the ratio as a fraction. Simplify. Answer: Written as a fraction in simplest form, the ratio 30 to 9 is Write the ratio 30 to 9 as a fraction in simplest form.
Example 1-1b Answer: Write the ratio 35 to 20 as a fraction in simplest form.
Example 1-2a Write the ratio as a fraction. Simplify. Answer: The ratio 4:24 is in simplest form. Write the ratio 4:24 as a fraction in simplest form.
Example 1-2b Answer: Write the ratio 9:36 as a fraction in simplest form.
Example 1-3a Convert 3 feet to inches. Simplify. Write the ratio 3 feet to 8 inches as a fraction in simplest form. If you have one unit that can be converted into the other, you must do so before you can make a ratio!!!! 9 Divide by the GCF, 4 inches. 2
Example 1-3a Answer: The ratio 3 feet to 8 inches can be written as
Example 1-3b Answer: Write the ratio 4 feet to 20 inches as a fraction in simplest form.
Example 1-4a Answer: The ratios in simplest form both equal So, 12:15 and 32:40 are equivalent ratios. Determine whether 12:15 and 32:40 are equivalent. Write each ratio as a fraction in simplest form. The GCF of 12 and 15 is 3. The GCF of 32 and 40 is 8.
Example 1-4b Determine whether 8:24 and 14:42 are equivalent. Answer: yes
Example 1-5a 1 to 15 or Recommended ratio Actual ratio 120 to 1,800 or POOLS It is recommended that no more than one person be allowed into the shallow end of an outdoor public pool for every 15 square feet of surface area. If a local pool’s shallow end has a surface area of 1,800 square feet, are the lifeguards correct to allow 120 people into that part of the pool? Answer: Since the ratios are equivalent, the lifeguards are correct to allow 120 people into the shallow end of the pool.
Example 1-5b WALLPAPER The instructions on a particular brand of wallpaper suggest using 1 quart of wallpaper paste for every 32 square feet of wallpaper hung. Bill purchases 8 quarts of wallpaper paste to complete a job that requires hanging 256 square feet of wallpaper. Is Bill using the proper amount of paste? Answer: yes
Click to see video of writing and simplifying ratios 1. http://glencoe.mcgraw-hill.com/sites/007888523x/student_view0/chapter6/lesson1/personal_tutor.html 2.http://www.glencoe.com/sec/math/msmath/mac04/course2/personal_tutor/personal_tutor.php?t=MAC2_7_1_2 3. http://www.teachertube.com/view_video.php?viewkey=e18e8c89552bbbcf5a29 4. http://glencoe.mcgraw-hill.com/sites/0078804906/student_view0/chapter4/lesson1/personal_tutor.html
Click to test your skills 1. http://glencoe.mcgraw-hill.com/sites/007888523x/student_view0/chapter6/lesson1/self-check_quizzes.html 2. http://glencoe.mcgraw-hill.com/sites/0078804906/student_view0/chapter4/lesson1/self-check_quizzes.html 3. http://glencoe.mcgraw-hill.com/sites/0078804833/student_view0/chapter6/lesson1/self-check_quizzes.html